The invention relates to the removal of solid tires, such as those used on industrial trucks, from the rims to which they are bonded, and more particularly to an economical and nearly pollution-free method and apparatus for effecting such removal.
The wheels of industrial trucks generally include an endless solid rubber (or synthetic rubber or plastic) tire sleeve molded and bonded onto a cylindrical band of seamless steel tubing which serves as a rim for the tire. The rim, in turn, is pressed with great force onto a wheel hub of the truck. The rubber tire is generally in a high degree of tension on the rim band. It is molded onto the band under high pressure and temperature, so that under ambient conditions, the tire goes into tension. A bonding adhesive agent is generally used between the rim and the tire, and during the molding and curing process, the tire is tightly bonded to the rim.
When the tread of the solid tire is worn down, the rim band and tire are removed from the wheel hub and replaced with a rim carrying a new tire. At this point, the worn tire may be removed from its rim by various means for salvage and re-use. Formerly, burning of the rubber tire off the steel rim was in wide use. However, the use of this method tended to distort the rim band due to the high and uneven temperatures, and due to the large amount of dense smoke associated with the burning away of the rubber, the burning method is now prohibited under most circumstances.
Another method sometimes used for removing the solid tires is to rotate the tire and rim and turn the rubber off the steel band with a cutting knife. Though this method is pollution-free, it creates extremely large quantities of rubber chips which must be disposed of. The turning down of one tire may result in several bushels of rubber chips. Another problem of the turning method is that many industrial tires become impregnated with hundreds of fragments of stone and metal. When the tires are removed by the turning method, the cutting knives employed for the process are rapidly worn down and often destroyed. Such great expense is thus involved that it is often not economical to salvage the rim bands by this method.
Other methods in wide use today for salvaging steel rim bands include heating of the tire and rim in various chemical baths. Boiling oil is sometimes used for the bath but more often a molten lead bath is provided. The tire and rim are dipped in the molten lead, whereby they are uniformly heated and the rubber tire is largely burned away. The method necessitates costly skimming operations to remove refuse material from the surface of the molten lead. Also, like the rubber burning method but to a lesser extent, the boiling method results in a large volume of dense smoke as the rubber is burned.
Because of the difficulties, pollution problems and expense of the foregoing methods, including both capital expenditures and operating expenses, many suppliers of industrial solid truck tires simply discard the entire rim and tire when the tire tread is worn to the point of replacement.